Increased cerebral blood flow and cardiac output following cerebral arterial air embolism in sheep
Date
2001
Authors
Williams, D.
Doolette, D.
Upton, R.
Editors
Advisors
Journal Title
Journal ISSN
Volume Title
Type:
Journal article
Citation
Clinical and Experimental Pharmacology and Physiology, 2001; 28(11):868-872
Statement of Responsibility
David J Williams, David J Doolette and Richard N Upton
Conference Name
Abstract
1. The effects of cerebral arterial gas embolism on cerebral blood flow and systemic cardiovascular parameters were assessed in anaesthetized sheep. 2. Six sheep received a 2.5 mL injection of air simultaneously into each common carotid artery over 5 s. Mean arterial blood pressure, heart rate, end-tidal carbon dioxide and an ultrasonic Doppler index of cerebral blood flow were monitored continuously. Cardiac output was determined by periodic thermodilution. 3. Intracarotid injection of air produced an immediate drop in mean cerebral blood flow. This drop was transient and mean cerebral blood flow subsequently increased to 151% before declining slowly to baseline. Coincident with the increased cerebral blood flow was a sustained increase in mean cardiac output to 161% of baseline. Mean arterial blood pressure, heart rate and end-tidal carbon dioxide were not significantly altered by the intracarotid injection of air. 4. The increased cardiac output is a pathological response to impact of arterial air bubbles on the brain, possibly the brainstem. The increased cerebral blood flow is probably the result of the increased cardiac output and dilation of cerebral resistance vessels caused by the passage of air bubbles.